This invention relates to an inductor particularly though not exclusively for use in a pulse width modulation amplifier.
Pulse width modulation amplifiers designed for use in broadcasting equipment incorporate inductors required to carry very heavy currents. It is therefore an important requirement that such inductors should produce as low a percentage of power loss as possible and therefore need to have a high Q factor.
It is well known that single circular coils of certain dimensions, e.g. the diameter being twice the length, have an optimum Q factor and that all other arrangements are inferior, although such other arrangements may be imposed upon the design where for practical reasons there is a limitation on physical dimensions. Thus, single circular coils have been used in the past.
Single coils inevitably generate external magnetic and electric fields which are liable to induce undesirable effects in nearby equipment. This is commonly avoided by enclosing the coil in a screen which may be formed by a metal cabinet.